New composite material design based on studies of tooth-composite and microbial i

描述(申请人提供)：拟议的研究将建立模型，以测试不同的策略和材料，以减少粘结界面的退化，目的是合成具有更强的抗细菌入侵能力的材料，并最终增加修复体的寿命。目的：研究树脂-牙界面缘在体外模拟人类口腔系统中的降解情况，并应用临床实践方法对修复牙进行修复。这项工作将寻求将修复牙齿的降解产物水平与细菌迁移到受损界面之间的关系联系起来。方法：将粘结树脂-牙本质标本与模拟人唾液酯酶(SHSE)孵育180天。降解后的标本将暴露于变形链球菌UA159单独或与干酪乳杆菌ATCC 746在基于恒化器的生物膜发酵罐(CBBF)中，模拟口腔条件7天。然后，使用活/死细菌生存能力试剂盒对标本进行染色。染色标本将使用共聚焦激光扫描显微镜(CLSM)单独评估边缘界面形态、细菌渗透和活性。目的：建立在树脂-牙本质界面形成生物膜后，原位检测变形链球菌和干酪乳杆菌基因表达的方法，并与非渗透面和浮游细胞进行比较。方法：全基因组分析(DNA微阵列)和单个基因转录分析(定量RT-PCR)将用于鉴定由物质降解产物激活的基因。利用荧光原位杂交(FISH)技术，利用预定义界面边缘间隙的树脂-牙本质标本，在体外和原位观察到与生理相关的细菌基因在树脂-牙本质界面的表达。目的：研究细菌对树脂复合体和粘结剂的降解作用。方法：将粘结剂和复合树脂材料(商业或实验性抗菌材料，见下文)分别在Buffer、SHSE、变形链球菌UA159+培养基或单独培养。材料的生物稳定性，通过降解产物的释放来衡量，将通过结合紫外光谱和质谱学的高效液相色谱(HPLC)来评估。目的：开发新型抗菌树脂，以减少细菌负荷和细菌侵入修复表面和沿树脂-牙本质边缘界面。方法：用共价偶联药物(甲硝唑、克拉维酸和氨苄西林)合成抗菌树脂。新型抗菌剂对基因表达和细菌微渗漏的影响将使用上述方法进行评估。这种材料设计方法对牙科保健界来说是新颖的，有可能改变复合树脂材料和粘合剂的配方、测试和应用方式。 公共卫生相关性：需要建立模型系统来评估口腔材料在唾液和细菌降解过程中发生的与生理相关的相互作用，以开发新的复合树脂配方的设计和应用，并向卫生保健从业者和患者提供准确的安全信息。拟议的研究将建立模型，以测试不同的策略和材料，以减少粘结界面的降解，目的是合成具有更强的抗细菌入侵能力的材料，并最终提高修复体的寿命。这种材料设计方法对牙科保健界来说是新的，有可能改变复合树脂材料和粘合剂的配方、测试和应用方式

DESCRIPTION (provided by applicant): The proposed research will establish models for testing different strategies and materials to reduce degradation of the bonded interfaces, with the intent of synthesizing materials with increased resistant to bacterial invasion and ultimately increasing the restoration's longevity. Objective: To study the degradation of resin-tooth interfacial margins with an in vitro simulated human oral system and teeth restored using clinical practice methods. This work will seek to correlate degradation product levels from restored teeth to bacterial migration into compromised interfaces. Methods: Bonded resin-dentin specimens will be incubated with simulated human saliva esterase (SHSE) for up to 180-days. Post degradation specimens will be exposed to S. mutans UA159 alone or with Lactobacillus casei ATCC 746 in a chemostat based biofilms fermentor (CBBF), mimicking oral conditions for 7 days. The specimens will then be stained using Live/Dead Baclight Bacterial Viability Kit. Stained specimens will be assessed individually for marginal interface morphology, and bacterial penetration and viability using confocal laser scanning microscopy (CLSM). Objective: To establish methods for reproducibly measuring gene expression of Streptococcus mutans and Lactobacillus casei in situ after formation of biofilms on resin composite, along the resin-dentin interfacial gap, and compared with impermeable surfaces and planktonic cells. Methods: Genome-wide transciptome analyses (DNA microarrays) and individual gene transcript analyses (Quantitative RT-PCR) will be used to identify gens activated by material degradation products. Using Fluorescent in situ hybridizaton (FISH) physiologically relevant in vitro and in situ spatial bacterial gene expression will be observed within the resin- dentin interface using resin-dentin specimens with pre-define interfacial marginal gap. Objective: To measure hydrolytic mediated degradation of resin-composites and adhesives by bacteria. Methods: Adhesive and composite-resin (either commercial or experimental anti-microbial, see below) materials will be incubated in buffer, SHSE, S. mutans UA159 +media or media alone. The biostability of the materials, as measured by the release of degradation products, will be assessed by high performance liquid chromatography (HPLC) combined with UV spectroscopy and mass spectrometry. Objective: To develop new antibacterial resins to reduce bacterial load and ingress over the restoration's surface and along the resin-dentin marginal interface. Methods: Anti-microbial resin will be synthesized using covalently coupled drugs (metronidazole, or Clavulanic acid and ampicillin). The effect of novel anti-microbials on gene expression and bacterial microleakage will be assessed using the methods described above. This approach to material design is novel to the dental health care community and has the potential to change the way composite resin materials and adhesives are formulated, tested and applied. PUBLIC HEALTH RELEVANCE: Establishing model systems to assess physiologically relevant interactions occurring during salivary and bacterial degradation of dental materials is required to develop the design and application of new composite resin formulations and to provide accurate safety information to health care practitioners and patients. The proposed research will establish models for testing different strategies and materials to reduce degradation of the bonded interfaces, with the intent of synthesizing materials with increased resistance to bacterial invasion and ultimately increasing the restoration's longevity. This approach to material design is novel to the dental health care community and has the potential to change the way composite resin materials and adhesives are formulated, tested, and applied